Timing switch



.1. NELSON TIMING SWITCH Filed March l0- 1920 jam??? ins Patented Apr. 26, 1927.

UNITED sures JOHN H. NELSON, O13 CHICAGO, ILLINOIS ECCO M AN'UFL'UJT [TI-HI.

Application filed March to, 1920. Serial No. 364,690.

My invention relates to iu'iprovements in timing E;\\'ilCl'lQS or commutator devices such as are enmloyed to control the ignition circuits of internal combustion engines.

The general object of this invention is to seciu'e increased elliciency. reliability and durability. I

hlore specifically stated, however, the object of this invention is to provide a torm of construction in which a rotary switch member will travel freely and be pressed against the track way with uuitorm pres sure withoutbinding or cramp ng; eii'ecls, without vibratory movement, without cramping ell'ects or shocks, with minimum development of centrifugal force. and without friction such as might damage the track way or the stationary contacts, the rotary moven'ient oi the traveling switch member being slow, its diameter large. relatively to that of the circular track way. its bearing surface upon the track way broad, and its freedom of accommodation to the track surface being at maximum.

A still more specific object of this invention is to provide a timing switch in which the movable member or coutactor may be ol such large diameter relatively to the cin cular track way along which the stationary contact members are located, that it may be mounted for relative rotation upon a ring carrier which encircles the timer shaft or actuator, whereby it may complete the circuit ot the trackway along which it rolls while revolving only a traction of a turn upon its own axis;

Also to provide means whereby the ring carrier, may be caused to revolve with the timer shatt or actuator in combination with means for swinging itunder resilient pressure about an axis ollset front that of the actuator to press the contactor againstv the trackway along a radius oi the actuator distant from that in which the axis of swing- .ingmoven'ient is located.

Heretotore the common conunercial prac' tice has been to provide the timer shaft with a crank arm with which a small roller is pivotally connected by a roller supporting arm which tends to swing outwardly from the timer shaft under resilient pressure and con tritugal force to hold the roller against the track way. This roller turns upon its own axis many times in the course of a single revolution of the timer shaft. Its shaft and the pivot pin which connect its supporting arm with the crank arnr are necessarily small and frequently become worn out or in'oken under the conditions of road travel to which motor driven vehicles are subjected. The rolier develops COIlSitlGtnblG centrifugal. tlorce and vibrates upon the track way with hammering ei'i'ects. causing' the latter to rap idly deteriorate. especially in the nonmetallzc or ii'isuiatingr portions thereof. The stationary contact members being harder. and more durable soon constitute projections 2n; wiich the roller strikes and over which it bounds thus not only breaking the circuit, but coi'zstantly increasing the vibratory movements of the roller and the violence of the impacts exerted by the roller under spring n'essure, and requiring ilt'requent replacei'nents oi. the timer mechanisn'i.

Attempts have been made to overcome the above mentioned di'lliculties experienceifi with the small, rapidly moving rollersby substituting; a ring rotativcly carried from the timer shatt by a slide mounting. the mountinn being pressed into an eccentric position by a spring, acting along; a radius of the timer sl'ia'i t which extends through the point of contact oi the roller with the track way. But so far as I am aware such structures have never been succes ful in practice, it not being possiole to rely upon the necessary sliding movement of the carrier which supports the ring due to cramping ellects de eloped in the slide movement and accentuated by the vibrations incident to road travel. I

In one aspect therefore. it is an object of my invention to provide a structure which combines the advantages of the prior art structures while eliminating the disad vantages above noted.

I maintain the plane of the roller bearing structure perpendicular to the axis oi the shalt by providing: the shaft with a grooveo portion into the groove of which the roller bearingstructure extends, the sides ot the groove engaging the sides of the roller bear ing structure to guide this structure in any bodily movement thereof with respect to the shaft as such movement occurs in response to thespring pressure. This feature of my invention is not to be limited to a swinging connection between the roller bearing structure and the shaft. I p

I will explain my invention more fully by reference to the accompanying drawing showing the preferred embodiment thereof and in which Fig. 1 is a view on line 1----1 f Fig. 2, illustrating a portion of the switch of my invention in elevation and other portions in section; Fig. 2 is a sectional view on line Q-Q of Fig. 1; and Fig. 2' is a sectional iew on line 3 3 of Fig. 1.

bike parts are indicated by similar char actors of reference throughout the different figures.

The timing switch illustrated includes a metallic shell 1, a mounting 2 upon which the shell is adjustably rotatable upon an axis co-incident with the axis of the shaft, and a spring 3 for maintaining the shell and its mounting in assembly, these characteristics being common to timing switches. As usual. an engine driven shaft 4 extends into the space enclosed by the shell. A ring of insulating material 5 within the shell is provided with arcuate contact terminals 6, each contact pertaining to an igniter circuit of which there is one for each cylinder of the engine. These contacts 6 are evenly spaced apart upon the ring of insulation 5, the inner face of the ring and the inner faces of the contacts forming a cylindrical surface or track way that is coaxial with the shaft. The contacts are provided with threaded stems T insulated from but mechanically assembled with the shell and extending sutliciently beyond the shell to form portions of binding posts with which the various sparking circuit conductors 8 are connected to constitute the contacts 6 as terminals of said circuits.

A rotary contactor is yieldingly supported from the shaft & and comprises inner and outer concentric rings 9 and 10 provided with interposed anti-friction members or balls 11 whereby the outer ring is adapted to freely rotate upon the inner one. The inner ring 9 is supported from the shaft by an arm 12 rigidly connected with the shaft and connected with the ring by a pivot pin 13, the ring having inwardly projecting ears to receive said pin. The arm 12 is connected with the shaft 4: by a collar 14 secured to the shaft by a set screw 15. This collar has a projecting stud over which a coiled spring 1 1 seats with the outer end of the coil bearing against the inner face of the ring 9 at a point distant from the pivot pin 13, the spring being disposed nearly at right angles to the arm 12. The spring pushes the ring outwardly in the direction of the track way formed by the insulating ring 5 and the arcuate contacts 6, the outer ring 10 being pressed against said track way in the line of spring pressure and adapted to roll along the track way when the shaft- 4: is rotated. A collar 16 is preferably applied to one end of the sleeve 1& in a position to cover the set screw 15 to prevent it from working loose. The inner ring or carrier 9 is formed of two members divided in the central plane thereof and peripherally grooved to receive the balls 11. This ring carrier 9 therefore constitutes an inner race way for the balls. The sleeve portion 1 1 of: the shaft is provided with a groove 17 that receives one portion of the inner raceway 9 whose sides are engaged by the sides of the groove to guide the roller bearing structure in any bodily movement thereof transversely of the shaft. This groove in the shaft conlines the roller bearing structure to one plane of movement with respect to the shaft. and prevents the roller bearing structure from being warped from its plane whereby the cylindrical con tacting face of the outer raceway 10 or rolling contact member is maintained in a posi tion to travel along the inner faces of the contacts 6 and their supporting ring 5. This :n'rangement insures requisite facial. contact between the outer raceway 10 and the con tacts ti complcmontal thereto.

It is quite apparent that the roller hearing structure, being mounted to swing upon the pivot shaft 13, will readily and quickly respond to the pressure of the spring 1.4- to maintain the travelling contactor it) in con stant engagement with the track way comprising the contacts 6 and their supporting ring 5, this result being secured irrespective of the high speed at which the shaft 4 may turn.

The rotary movement of the travelling contactor 10 upon the carrier ring 9 during any single revolution of the shaft 4 will be equal to the difference in diameter between the travelling contactor 10 and the relatively stationary track way formed by the insulating ring 5 and the arcuate contacts 6. Therefore, the contactor 10 rotates upon its own axis only a fraction of a turn while the shaft 4 rotates a complete turn although the contactor 10 touches every point along the track way throughout its circuit during such revolution of the shaft. the principal movement being that of bodily translation due to the movement of the eccentrically supported carrier 9 which, of course, rotates with the shaft being pivotally connected with it.

lVhen itis desired to advance or retard the sparking in the cylinders of the engine the shell 1 is turned in one direction or the other by lever niechanisn'i connected with the shell at 18 to turn the ring 5 in one direction or the other to secure the necessary angular readjustment in the positions of the contacts 6 without in any manner disturbing the me chanical and electrical inter-relation of the roller bearing structure and the contacts since the shell 1 and the inner faces of the ring 5 and contacts 6 are co-axial with each other and with the shaft.

lVith the exception of the roller bearing structure and the manner of v mounting the same herein set forth and the sleeve 14 with its groove 17, the timing switch illustrated is one which is very commonly found in one make of automolules, there even being, in the other timers, the. sleeve 1'1 assembled therewith in the manner illustrated, such sleeve however having no groove 17. These other timing switches may readily be converted into the timing switches of my invention b ren'ioving the sleeves upon the shaft thereof, replacing such sleeves with the sleeves 14 of my construction and having the roller bez-iring structures swingingly mounted thereupon and also having the springs l-t interposed between the inner raceways of such roller bearing structures and the sleeves let.

lVhile I have herein shown and particu larly described the preferred embodiment of my inventirm, I do not wish to be limited to the precise details of construction shown as changes may readily be made without departing from the spirit of my invention, but having thus described my invention I claim as new and desire to secure by Letter: Patent the following 1. In a device of the class described, a shaft; a casing having contacts; inner and outer races about the shaft; anti-friction elements between the races; a collar on the shaft and having an arm pivoted to the inner race; and a compression spring between the collar and the inner race, the spring constituting means for holding the races yieldably in eccentric relation to the shaft,

whereby the outer race will traverse the contacts.

2. A device of the class described, constructed as set forth in claim 1, and further characterized by the fact that the spring is of helical form the collar and the inner race having studs which receive the ends of the spring.

23. In a device of the class described, a shaft, a casing having contacts; inner and outer races about the shaft, the outer race traversing the contacts; antifriction elements between the races; means for pivoting the inner race to the shaft; and a spring interposed between the inner race and the shaft for disposing the races in eccentric relation. to the shaft,

4. A rolling contact device adapted for use in connection with a timer shell and its fixed contacts, comprising inner and outer rings provided with anti-friction elements therebetween, an extension. formed on the inner ring, a pivot pin in the extension, an actuator member, of forked construction having its furcatious engaging the ends of the pin to provide an extended fulcrum for said rings, and a spring arranged between said actuator member and the inner ring to press the contact device toward the timer shell and its fixed contacts.

In witness whereof, I hereunto subscribe my name this eighth day of March, A. 1)., 1920.

JOHN H. NELSON. 

